Luria left in the lurch: unfulfilled promises are not valid tests

Complex Motor Function in Humans: Validating and Extending the Postulates of Alexandr R. Luria

OBJECTIVE

We used functional brain imaging to reevaluate Luria's postulates and to elaborate the neural circuitry underlying performance of complex motor tasks.

BACKGROUND

The anatomic organization and physiologic functioning of the normal human motor system have great significance for understanding motor dysfunction and remediation in neurology. Working with victims of penetrating head injuries, noted Russian neuropsychologist Aleksandr R. Luria designed several tests of fine motor control to understand their difficulties with complex voluntary movements. This led to his postulates that such function involves the premotor cortices and their interaction with the parietal lobe.

METHOD

Six healthy young adults performed the hand imitation, fist-scissors-gun, and piano key tasks during blood oxygen level-dependent functional magnetic resonance imaging at 3 T.

RESULTS

All 3 tasks revealed activation of both premotor and parietal cortices. Furthermore, while hand Imitation relied more on the ventral premotor area and right parietal lobe, fist-scissors-gun and piano key relied more on the supplementary motor cortex.

CONCLUSIONS

We postulate that differences in task-dependent activations across these tasks relate to degrees of sequential movement, pacing, and imitation. These results uphold Luria's original hypotheses, and extend that work by providing a further characterization of the motor areas involved in complex motor behaviors.

Criminal responsibility and mental health experts: the A,B,Cs of cross-examination

Experts from the field of behavioral sciences are regularly called upon in criminal prosecutions to offer an opinion as to an accused person's mental state at the time an alleged crime was committed. Within the confines of a criminal courtroom, perception often becomes reality. From a lawyer's perspective, the author attempts to reveal how the optics of a trial can become better aligned with actual fact through the adversarial process. Although written by a prosecutor, the upcoming commentary on the A,B,Cs of cross-examination should equally assist the defence counsel who must prepare his/her expert, the judge who must decide what weight to put on the testimony and the mental health expert who ultimately will be obliged to answer the questions.

Validity of the Luria-Nebraska language scales in aphasia

The language scales of the Luria-Nebraska Neuropsychological Battery (LNNB) were administered to patients classified as either Broca's (n = 7) or Wernicke's (n = 7) aphasics. Group comparisons were made on the standard scales (e.g., Receptive Speech, Expressive Speech, Reading & Writing) and on 13 factor-analytically derived subscales (McKay & Golden, 1981). Results indicated that the standard T-score profile failed to discriminate the distinctively different language syndromes. Only two of the 13 factor scales differentiated the groups. Although Wernicke's patients were more impaired than Broca's patients on factor-analytically derived measures of basic language comprehension, it was concluded that the subscales added little to the standard profile in terms of aphasia syndrome identification. Distinctively different profiles of impaired and retained language abilities did not emerge on the LNNB factor scales. The battery cannot be recommended for use with aphasic patients.

Lateralizing brain damage with the Luria-Nebraska Neuropsychological Battery: diagnostic effectiveness as compared to the Halstead-Reitan Neuropsychological Test Battery

This investigation examined the ability of the Luria-Nebraska Neuropsychological Battery (LNNB) to lateralize brain damage, since substantial statistical and methodological issues have been raised regarding the initial LNNB lateralization validation study. A comparison was then made of the ability of the LNNB and the Halstead-Reitan Neuropsychological Test Battery to lateralize brain damage. Both neuropsychological batteries were administered to 30 predominantly left- or right-hemisphere-damaged subjects (15 in each group) with discriminant analysis classification procedures demonstrating similar, above chance, accuracy in lateralizing cerebral dysfunction. Cross-validation of objective clinical rules designed to aid in LNNB test interpretation resulted in classification of brain damage and lateralization at levels below reported values from the test developer's laboratory. The limited role such simplistic rules have in assessment is discussed, as is the need to evaluate dimensions of test usefulness other than those related to gross diagnostic decisions (e.g., presence or laterality of brain damage) in determining the instrument of choice for clinical neuropsychological practice. More research is recommended to fully define the limits of the clinical utility of the LNNB.